This invention relates to worm-gear speed reducer assemblies, and, in particular, to an improved seal for the speed reducer's shafts.
The relative commercial usefulness of worm gear systems is based in part upon the ability for the gearbox seals to prohibit the egress of lubricants; the ability for the gearbox seals to prohibit the ingress of debris contaminants; the ability for the gearbox seals to minimize heat generation; and the ability for the gearbox seals to minimize wear of the seal itself and/or its mating shaft. Hence, the seals of worm gearboxes play an important part in the commercial usefulness of worm gear systems.
However, currently seals for worm gearboxes have a much lower life than any other gearbox component. Lubricant leaking indicates seal failure. Leaking lubricants into the environment is generally unacceptable and replacing seals is time consuming and costly. Debris tends to scratch and damage the seal elastomer and/or abrade and wear the shaft or shaft sleeve. The seals are also adversely affected by chemical reactions with the lubricant, by wear imposed by contact with the shaft or shaft sleeve, and by heat that can embrittle the elastomer. The seal is likely to be replaced one or more times over the useful lifetime of the gearbox.